1. Field of the Invention
This invention relates to organopolysiloxane elastomers with improved electrical properties and to a method for obtaining such elastomers.
2. Description of the Prior Art
Organopolysiloxane elastomers are now well known materials which find application in many technical fields. For example they are employed in the production of high temperature gaskets, as encapsulants and as electrical insulation. Some electrical applications of organopolysiloxanes require that the elastomer shall be resistant to tracking following arcing across its surface. The arc resistance of organopolysiloxane elastomers is generally satisfactory but for certain specific applications there is a demand for a significant improvement in this respect. One method which has been proposed for improving the arc resistance of such elastomers consists of incorporating into the elastomer-forming composition a proportion of aluminum hydrate. The incorporation of this compound can result in a significant improvement in arc resistance. However, it has been found that at the same time, after exposure to moisture, the elastomer suffers a marked deterioration in its resistance to breakdown under an applied voltage.